What exactly is psoriasis?

Posted on 18 February 2014

Said to be one of the most common skin conditions, psoriasis is an inflammation of the skin in which skin cells reproduce at a rapid rate resulting in scaly patches. Yet in many ways it is still somewhat baffling. Dr Niels Holm, a dermatologist at Mediclinic Vergelegen, says not a day goes by without him seeing a patient who has psoriasis. Here, he answers some basic questions.

Do we now know what causes psoriasis?
No, we don’t know the absolute cause for sure. We know there is a genetic implication, in that familial history repeats itself, and we are aware of several triggers, such as certain medications or infections. The surest we can be is to say that it is a genetic condition with more than one aspect: It involves the immune system, and is related to genetics and inflammation issues.

About three percent of the population can carry psoriasis, but some have it without even realising it. They may simply have roughness on their elbows, with no pain or itchiness, for instance. But then others may have psoriasis evident across 80% of their body, and they may also have joint pain.

Can lifestyle factors like stress contribute to psoriasis?
Stress is high on the list of potential triggers. In children, infections, like those from tonsillitis or streptococcal infections, can precipitate an outbreak of psoriasis – but so can many infections. Certainly, psoriasis can also form where there has been an injury, such as on an old scar or burn wound. Certain medications increase the risk factors: beta-blockers, some anti-malarials, and even some cholesterol-lowering meds. Often, in patients who have undergone a serious medical intervention, like an operation, we see flare-ups.

Does psoriasis commonly also lead to joint/arthritic problems?
It does in about 5-10% of patients. It can also affect the soft tissues around the joints. So psoriasis is almost like an autoimmune disease in this respect; it’s linked to autoimmunity and so overlaps with many of the body’s systems. It the condition is a multisystem thing, the joint psoriasis (psoriatic arthritis) can be debilitating. Then, it requires more assertive therapeutic treatment.

There are several forms of psoriasis. Which one is most common?
Plaque psoriasis, where chronic plaque patches appear on the same place. Other types, such as guttate or pustular, are less common but we do see them too.

Is treatment typically topical?
There are many topical options for more mild cases, things like calcipotriene (vitamin D analogues), are used. Old methods include coal tar preparations, which are still used. There are also readily available moisturisers to dissolve the scales on the plaque patches. Cortisone creams are often used, but cortisol should not be taken orally or via injection, as this may cause complications. Then, for sensitive areas like the face, we can use calcineurin blockers. Other treatments, for more severe cases, are offered by the various light (photo) therapies: narrowband UVB, PUVA or excimer. These physical treatments are safer, but they are more time-consuming, as they typically require two sessions per week.

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Published in Dermatology

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